The present invention relates generally to tool bars for supporting and positioning agricultural working implements and in particular is directed to a multi-section agricultural tool bar in which the positions of the various sections are controlled by a plurality of hydraulic cylinders.
A tool bar for agricultural use is a device adapted to be pulled by a vehicle, such as a tractor, and on which ground engaging implements are securely mounted. The tool bar provides support for the implements so that their placement and orientation relative to the ground remains generally unchanged during operation, and it also maintains a fixed lateral spacing between the working implements. The term "implements" is intended to have a broad meaning in the present disclosure and includes, but is not limited to, such agricultural tools as planters for seeds, coulters, fertilizer applicators, or any combination of these devices.
The development of tool bars has lead to increasingly longer length providing a wider swath coverage in reducing the number of passes required in the cultivation/ planting process for a given area. This lengthening of the tool bar and corresponding increase in the number of working implements supported thereon, has been made possible, in part, by the availability of increasingly powerful tractors and has resulted in a reduction in the time and the fuel required to cultivate or plant a field of a given size. Multi-section tool bars of the prior art generally include first and second wings pivotally mounted to a main, or center, frame which is provided with support wheels. The wings or "bars" are pivoted between a use position in which the wings extend laterally with respect to the main frame and transverse to the direction of travel of the vehicle, and a road travel or storage position in which the wings extend either rearwardly of the main frame and parallel to the direction of travel of the vehicle or are folded upward so that the width of the entire retracted mechanism is no longer than the length of the main frame. The present invention relates to the latter flexible tool bar arrangement wherein the wings are folded vertically when the tool bar is in the retracted position for transport or storage.
Prior art vertically folding tool bars suffer from various operating limitations. One of the primary disadvantages of these systems relates to the transportability and maneuverability of the implement carried by the apparatus or tractor, as the case may be. Even in the fully retracted position, some of the earlier systems generally project laterally outward from the main frame of the tool bar, increasing the overall width of the tillage apparatus. In addition, in the retracted position the flexible wings extend a considerable height above the tractor and the implement carrying structure requiring that the wings be removed from the main frame in order to move the tool bar assembly into an enclosure for storage or repair unless the enclosing structure is provided with an over-sized access door. With increasing tillage implement size and pulling vehicle power, tool bar lengths have correspondingly increased requiring even larger access openings to accommodate current flexibIe tool bar arrangements.
The increasing size of multi-section tool bars has increased the susceptibility of these systems to damage. For example, the greater lengths and weights of the wing sections have increased the susceptibility of these systems to damage during transport in the retracted position due to excessive vibration and large forces applied thereto with the traversal of irregular road surfaces. In addition, the wing sections of the tool bar may be subjected to high impact forces due to contact with overhead structures, trees and utility lines. Contact with overhead utility lines may not only result in damage to the work implement but also, of course, poses a serious threat to the safety of the farmer. Another danger involving over-sized tool bars relates to their transport in the folded position. The higher the center of gravity, the more unstable is the transported tool bar with attached implements and the more unsafe is the transport operation particularly on rough, sloped terrain.
The present invention is intended to avoid the aforementioned limitations of prior art multi-section tool bars by providing a tool bar which is more easily and safely transported, does not require large storage and repair structures having correspondingly large access openings, and is compatible with a conventional pulling vehicle hydraulic system for agricultural implement positioning.